Is this the week they're having the hot air balloons in Kingsport? Have any of them been flying over?
From: <http://www.doberman.org/articles/puppy.htm>
Second Fear Imprint Period (6 - 14 Months) The Second Fear Imprint Period is similar to the one that occurred during the socialization period, but, it is much less defined. It occurs as dogs enter adolescence and seems more common in males. It is often referred to as adolescent shyness. Your dog may suddenly become reluctant to approach something new or suddenly become afraid of something familiar. This behavior can be very frustrating to the owner and difficult to understand because its onset is so sudden and, seemingly, unprovoked. If you notice this behavior, it is important to avoid the two extremes in response: Don't force him to do or approach something frightening to him and don't coddle or baby him. To get through situations that make your dog fearful, be patient, kind, and understanding. Desensitize him to the object or situation by gradually introducing him to it and using food rewards and praise to entice him to confront the fearful object or situation. Do not coddle or reassure him in any way that will encourage his fearful behavior. Do not correct him either. Simply make light of it and encourage him give him food rewards as he begins to deal with his fear better. Make sure you lavishly praise his attempts! This phase will pass.
Have you added anything new to the backyard? A new picnic table or lawn chairs for example? Are the garbage cans where they usually are/supposed to be? Lawnmower hasn't been left out has it? Sometimes just any little seemingly insignificant change can trigger such a behavioral change. No bugs hatching out are they - like June bug season?
Interesting mystery to solve. Be patient and good luck!
Debbie